[Qemu-devel] [PATCH] xen_disk: Always set feature-barrier = 1

[Qemu-devel] [PATCH] xen_disk: Always set feature-barrier = 1

[Kevin Wolf]

The synchronous .bdrv_flush callback doesn't exist any more and a device really
shouldn't poke into the block layer internals anyway. All drivers are supposed
to have a correctly working bdrv_flush, so let's just hard-code this.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---

I'm not sure what feature-barrier really means, but this is the closest thing
to what we used to do. Should this really be dependent on whether or not we are
using a writeback cache mode?

Also, someone should really get rid of that #include "block_int.h" in xen_disk.
Things defined there are not a device's business.

 hw/xen_disk.c |    5 ++---
 1 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/hw/xen_disk.c b/hw/xen_disk.c
index 8a9fac4..286bbac 100644
--- a/hw/xen_disk.c
+++ b/hw/xen_disk.c
@@ -620,7 +620,7 @@ static void blk_alloc(struct XenDevice *xendev)
 static int blk_init(struct XenDevice *xendev)
 {
     struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
-    int index, qflags, have_barriers, info = 0;
+    int index, qflags, info = 0;
 
     /* read xenstore entries */
     if (blkdev->params == NULL) {
@@ -706,7 +706,6 @@ static int blk_init(struct XenDevice *xendev)
                       blkdev->bs->drv ? blkdev->bs->drv->format_name : "-");
         blkdev->file_size = 0;
     }
-    have_barriers = blkdev->bs->drv && blkdev->bs->drv->bdrv_flush ? 1 : 0;
 
     xen_be_printf(xendev, 1, "type \"%s\", fileproto \"%s\", filename \"%s\","
                   " size %" PRId64 " (%" PRId64 " MB)\n",
@@ -714,7 +713,7 @@ static int blk_init(struct XenDevice *xendev)
                   blkdev->file_size, blkdev->file_size >> 20);
 
     /* fill info */
-    xenstore_write_be_int(&blkdev->xendev, "feature-barrier", have_barriers);
+    xenstore_write_be_int(&blkdev->xendev, "feature-barrier", 1);
     xenstore_write_be_int(&blkdev->xendev, "info",            info);
     xenstore_write_be_int(&blkdev->xendev, "sector-size",     blkdev->file_blk);
     xenstore_write_be_int(&blkdev->xendev, "sectors",
-- 
1.7.6.4